Powder coating is an important industrial process that allows for the coating of various materials with a surface film of varying compositions. Metallic pieces or objects often undergo a powder coating process in place of paint, with the deposited coating having various desirable properties, such as color and durability. Typically the coating consists of a plastic, often a thermoplastic, base material that is applied to the substrate as a powder then cured to form a uniform and cohesive coating or film across the substrate.
The powderized coating material is electrostatically charged and sprayed towards a grounded substrate. The electrostatic potential between the powder and substrate attracts the powder to the substrate surface. Additionally, the use of the electrostatic potential between the two elements ensures that an even and complete coating is achieved across the entire surface of the substrate. Once coated, the substrate is cured to achieve the final coating. The curing process often involves heating the deposited powder until it liquefies to form the film, or coating, across the substrate surface. The cured substrate and coating is then cooled, completing the coating process.
Powder coating has many benefits as a coating process. Besides the even coat, any residual or overspray of the powder can be collected and reused in future powder coating processes. This means the powder coating process is very efficient as only the necessary amount of powderized coating material is used per piece of coated substrate. However, the desired coating material must first be powderized before the powder coating process can occur. Typically this involves melting a base material and adding any colorants or other desired additives, to form a liquid form of the coating material. The liquid coating material is then cooled into sheets of solid coating material that is then broken up or pulverized to form the coating powder. Once deposited on a substrate and cured, the powdered coating material re-melts to form a liquid that covers the surface of the substrate in a film of the coating material.
As such, the process of forming the powderized coating and depositing and curing the powderized coating occur as two distinct processes and in two distinct physical locations. Often this means a supplier formulates and produces the powder and a user applies and cures the powder to a desired substrate.
Forming the powderized coating often requires melting and blending the coating materials which are then cooled and processed into a powder. Once deposited the powder is heated to melt it into the final coating. This means in the conventional methods, the coating material goes through at least two complete heating and cooling cycles to form the final coat on a substrate.
The powder coating art would greatly benefit from a system and method that is more efficient and requires less energy than the conventional methods.